It is common surgical practice to use bypass grafts to help reestablish coronary artery circulation when a portion of the coronary artery is stenosed. Such a procedure is typically referred to as a Coronary Artery Bypass Graft (CABG) procedure. Typically the graft vessel used in bypassing the stenosed portion of the coronary artery comprises one or more segments of the patient's saphenous vein which is taken from his leg. The saphenous vein is dissected free from the leg, its side branches tied off or ligated, and the vein removed. The vein graft is then washed free of blood, and cut into portions of suitable length. Each portion is then passed to the surgeon who trims the ends of the graft before anastomosing the graft to the aorta and the coronary artery. Other graft vessels such as the radial artery in the arm can also be used. In addition, it is common practice today for the surgeon to redirect one of the internal mammary arteries (IMA) in the chest to the stenosed portion of the left anterior descending (LAD) artery on the heart. The end of the IMA near the patient's diaphragm is transected, the artery is mobilized by dissection and ligation of side branches, and then the end is joined to the LAD, just distal to the blockage. For multiple bypass surgery, a combination of the redirection of the IMA and the grafting of vessels to the diseased coronary arteries is often used.
Some surgeons choose to complete all the proximal anastomoses to the aorta before commencing the distal anastomoses to the coronary arteries. In contrast, others choose to complete the distal anastomoses first. Regardless of the order, when undertaking the distal anastomoses to the coronary artery, it is important that the vessel graft be held steady and adjacent the coronary artery, with a minimum of vascular trauma and a minimum of visual and surgical obstruction by instruments in the narrow operative field.
The speed of performing such anastomoses can become extremely critical as well. Often the coronary artery is occluded during the procedure so that the anastomoses can be performed more easily. It is very important to reconnect the supply of blood to artery as soon as possible in order to minimize or prevent damage to the patient. Blood vessels are now normally anastomosed end-to-end or end-to-side by suturing techniques. Conventionally, to suture two vessels together, a surgeon passes the pointed tip of a curved suturing needle, having a suture attached to the blunt end, through the coronary artery wall from inside the lumen. The needle is then passed through the graft vessel wall from the outside. Then, the surgeon grasps the tip of the needle which has been forced through the tissues with a needle holder and pulls the needle through the tissues, the suture following the curved path of the needle. Usually a knot or button is present at the trailing end of the suture to anchor the first stitch. After the surgeon has pulled the suture entirely through the tissues to tension the first stitch, he or she then forces the tip of the needle through the coronary artery again, at a location spaced from the first stitch, until the needle again goes through the coronary artery and back out through the graft vessel. Again, he grasps the tip of the needle which has been forced through the tissues, applies tension to the needle pulls the entire suture through the tissues to complete the second stitch. This process is repeated again and again, with the surgeon tensioning the suture after each stitch to draw the tissues together thereby creating a running or continuous stitch composed of individual thread loops, which extends around the graft vessel.
In a CABG, access to the heart is gained through a median sternotomy. Less invasive procedures are being widely adopted in order to reduce the recovery time and the associated post-operative pain of the patient. One procedure, known as a MIDCAB (minimally invasive direct coronary artery bypass) is performed through an intercostal (between the ribs) incision or thoracotomy. Endoscopic procedures for other parts of the body and involving the suturing of tissue are well known in the surgical art.
Needless to say, such suturing techniques are a tedious and time consuming task, especially when access to the surgical site is limited. Suture anastomoses procedures generally take the skilled surgeon several minutes to complete for each anastomosis. An example of a device which was designed to help a physician in performing suturing can be found in U.S. Pat. Nos. 5,437,681 issued to Meade, et al. on Aug. 1, 1995 and 5,540,705 issued to Meade, et al. on Jul. 30, 1996. However, there are a number of disadvantages to the device disclosed in those references. In those devices it is the device itself which drives the needle through the tissue. Many physicians do not like this design because they like to have more control of needle placement and feel the resistance of the needle passing through the tissue when doing the procedure. Surgeons want the speed and efficacy offered by the new devices, but surgeons also want to maintain the benefits of the traditional suturing techniques.
It is also important to surgeons to be able to use various types of surgical needles which are commercially available today. This is because different surgical procedures require different needles (and suture filaments) and because of differences in surgical technique. Needles may be semi-circularly shaped (having a single center of curvature) of different radii. Others are arcuate, and may have multiple centers of curvature. It is desired that a needle-holding device overcome the shortcomings of the prior art already cited, yet also be able to accommodate these various needles.
Sometimes it is necessary or unavoidable for the surgeon to apply a side force to the needle as it is being passed through the tissue. This may happen, for example, if the surgeon has placed the needle into the tissue, and then raises or twists the needle holder to augment the position of the tissue captured. The side force could result in the deflection of the needle while held in the end effectors of the needle holder. This is not so much a problem if a second needle holder is used to clamp onto the pointed end of the needle and pull it from the tissue. A single surgical device having both the ability to place the needle into tissue and to pull the needle from the opposite side of the tissue so as to make a stitch with one device, yet never letting loose of the needle, must allow for the needle deflection sometimes encountered. All of this must be done while managing the trailing suture filament attached to the needle so that the filament is not inadvertently damaged or tangled.
Typically the step of the suturing technique that requires the most time and care is the accurate placement and penetration of the needle into the tissue. Once the needle is penetrated into the tissue so that the needle tip exits the tissue, the surgeon may quickly pull the needle and trailing suture filament through the tissue. The placement and penetration of the needle into the tissue, therefore, is preferably controlled by the surgeon for some surgical procedures, rather than automated as with some of the prior art devices. Furthermore, it is important for the surgeon to sense tactilely the force of the needle penetrating into tissue in order to understand the type of tissue being penetrated or to know if obstructions are in the way of the needle. This control and tactile feedback may be provided by using a surgical instrument to hold the needle near the attachment to the suture filament, placing the tip of the needle into the tissue, and then rotating the instrument about its longitudinal axis in order to penetrate the tip of the needle through the tissue. Rotation of the instrument is accomplished by the medial rotation of the surgeon's forearm. (This is referred to in the art as supination for when the palm is turned upward and pronation for when the palm is turned downward.) What is needed, therefore, is a surgical instrument that allows the surgeon to control and have tactile feedback for the step of needle placement and penetration, yet automates the less critical step of pulling the needle and filament through the tissue.
The present invention provides a device and method that overcomes the shortcomings of the prior art and helps the physician to suture bodily tissues easily and quickly with a single instrument. It may be used for many different shapes of surgical needles, not only semi-circular ones. The present invention provides a device that can both place the needle into tissue, and pull the needle from the opposite side of the tissue, without letting go of the needle. It can do so even though a side force may be applied to the needle. The present invention provides a stationary arm for holding the needle so that the surgeon may retain control and tactile feedback of the step of placing and penetrating the needle into the tissue. The present invention provides a movable arm to automate the pulling of the needle and filament through the tissue. The present invention provides for management of the suture filament as the needle is manipulated through the tissue. It may be used in open surgeries as well as in the less invasive and endoscopic procedures. All of these attributes make the present invention especially useful for performing and easy and quick vascular anastomoses such as for a CABG procedure.